The interrelationship of calcium and magnesium absorption in idiopathic hypercalciuria and renal calcium stone disease.
OBJECTIVE
A decreased concentration of magnesium in the urine is a risk factor for renal calcium stone disease that may be caused by decreased enteral absorption of magnesium. We analyze the possible reciprocal influences of enteral absorption of calcium and magnesium in patients with renal stone disease.


METHODS
We measured the fractional enteral absorption of 47calcium and 28magnesium in 11 patients with renal calcium stone disease, including 8 with and 3 without hypercalciuria. Two tests were performed using calcium and magnesium, respectively, followed by another test in which the enteral absorption of calcium and magnesium was measured after both cations were administered together.


RESULTS
We noted no clear influence of either cation on the absorption of the other in the 3 patients without hypercalciuria. However, in the 8 hypercalciuric patients enteral calcium absorption decreased after the concurrent administration of magnesium and enteral magnesium absorption increased after the concurrent administration of calcium. Each effect was proportional to the other.


CONCLUSIONS
The results of this study indicate that the oral supplementation of magnesium in patients with hyperabsorptive hypercalciuria and renal calcium stone disease is favorable because it decreases calcium absorption and increases magnesium absorption. Both factors may reduce risk factors for renal calcium stone formation.
de Swart
P M
PM
Department of Medicine (Division of Nephrology), Academic Medical Center, Amsterdam, The Netherlands.
Sokole
E B
EB
Wilmink
J M
JM
D000328:Adult; D002118:Calcium / Q000378:metabolism* / Q000652:urine; D002128:Calcium Metabolism Disorders / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006934:Hypercalcemia; D007408:Intestinal Absorption; D007669:Kidney Calculi / Q000150:complications / Q000378:metabolism*; D008274:Magnesium / Q000378:metabolism* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D012008:Recurrence
D008274:Magnesium; D002118:Calcium